*****************ENGLISH VERSION*****************Here is a particular article on this astronomical-news-related blog, since it concerns the story of an extremely rare event which I attented on September, 1st 2016 : a bright meteor passing in front of the Andromeda Galaxy (M31).Note : Meteors or shooting stars are tiny piece of dust coming from space (comets) which release light when they fall down the Earth, through our rough atmosphere.Their speed is at this moment dramatically high, producing a great warm-up (combustion), hence the releasing of a bright light trail in the sky.Outline of the article (interactive) :• The backdrop •• UFO ? | The wondering step •• Meteor ? | The searching step •---------------------------------------

• The Backdrop •

During the night from August 31 to September 1st, I had scheduled to photograph wide-field views of the Milky Way. Noticing the increadible darkness and quality of the sky, I motivated myself to draw my telescope and equatorial outdoor in order to capture this bright target that is indeed the Andromeda Galaxy. Given it was my first attempte at capturing this object at prime focus of my scope, I was excited to see how the result would be.Once my camera was installed on the ocular holder, I started to take some test frames. On the first one, I was lucky enough (or not at all) to have an artificial satellite crossing the galaxy :(image)60 secs, ISO 6400, 800 mmSo, I initiated a 30-frames serie of 30 seconds exposure time each, and decided to go back home to get a bit warmer...When I come back and have a quick look on my pictures to check if they were correct, I saw this strange image where a very orange-colored-bright trail crosses the whole field of the Andromeda Galaxy.My hearts started to beat a bit quicker, wondering of what this unknown object would be. At that moment, I thought it could be a meteor ...

• UFO ? | The wondering step •

Instead of be influenced of my strong feeling which tend to say it is a meteor, I became more reasonable : capturing such a phenomenon does not regularly occur, to not to say almost never. Indeed, it is rare to record the crossing of a meteor using an instrument with high magnification and even rarer if this meteor passes just in front of a deep sky object as M31.

★ A jetplane ?

Reams of elements can not defend the idea of a plane :- In the picture, only one light line is visible, whereas a plane is actually fitted with lights on each wing.- Any flash light is not visible in the image.- The plane could not come in front because at this time of the night, M31 was almost at the Zenith (90° altitude).- ... etc

★ An artificial satellite ? An iridum flare ?

After a lot of research have been done, as well as on heavens-above.com or on Stellarium software, no satellite or Iridium were scheduled to cross this particular region of the sky at this moment.Plus, no satellite could have reflected the sunlight with such an amount of light, at this time of the night. (~1:47 am local time)Moreover, a space debris could not have produced this light continously.

★ Specialist's Feedback

To reinforce or wipe my arguments out, I decided to ask advanced amateurs astronomers. A web forum as "Webastro" or a facebook group as "Astronomes et Astrophotographes Amateurs" or the Space Weather community helped me for my investigation.It is essential to discuss with well-experienced people who could rapidly give you an answer.

• Meteor ? | The searching step •

All tends to argue the meteor. Differents elements in the picture can explain it for :- The strong brightness of the trail is stunning- The orange color of the trail is puzzling- Zooming in, we can slightly see that the trail is split from the upper part (a duplication on one side).- The trail is not continous and homogeneous

★ A characteristic orange color

All the shooting stars are not green ! They can sometimes appear yellow, red or orange. Each color match up with a main chemical product which composes this comet's dust.So, the orange on my image indicates the meteor's composition : Sodium.

★ A material ejection

Every particule coming from space and burning in our atmosphere released a quantity of material more or less significant caused by the strong heating of the combustion.In my image, if we zoom in, and adjusting the settings with a software, I realised that this line was actually not clearly bordered. The upper part is made of an anomaly.

Now, it is beyond the shadow of a doubt that this trail is actually made by a meteor burning up in the atmosphere !

This event will remain for a while the lukiest one I have ever lived in astronomy !